Gaseous electric discharce tubular lamp



Oct. 6, 1936. K. WIEGAND GASEOUS ELECTRIC DISCHARGE TUBULAR LAMP Filed June 18, 1935 INVENTOR Patented Oct. 6, 1936 UNIT GASEOUS ELECTRIC DISCHARGE TUBULAR LAMP Kurt Wiegand, Berlin-Tempelhof, Germany, assignor to General Electric Company, a corporation ct New York Application June 18, 1935, Serial No. 27,233

' In Germany July 20, 193% 3 Claims. (Cl. 176-122) The present invention relates to gaseous electric discharge tubular lamps generally and more particularly the invention relates to such devices having thermionic electrodes sealed therein at the ends thereof and a diiiicultly vaporizable material therein, such as sodium, potassium, I lithium, cadmium or zinc, the vapor of which is light emitting during the operation of the lamp.

The metal vapor pressure in such devices is comparatively low and the vapor condenses readily forming light absorbing deposits on the part of the tubular lamp container surrounding the discharge path as this is the coolest part of said container during the operation of the lamp. The efficiency of the lamp is thus considerably reduced.

The object of the present invention is to'increase the efficiency of tubular gaseous electric discharge vapor lamps the gaseous atmosphere of which consists of or comprises the vapor of a diflicultly vaporizable material. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular 25 description.

In accordance with this object the invention comprises an elongated tubular container, thermionic electrodes sealed therein at each end thereof, a pair of open-ended metal tubes axially 35) mounted in each end of the container and surrounding said electrodes, and two elements of material having good heat conducting characteristics attached to said metal tubes and extending from said metal tubes toward the middle of said container along the discharge path in said container. The heat conducting elements are mounted in the discharge path and conduct the heat generated at the electrodes from the ends of the tube toward the center thereof so that the heat generated in the lamp is evenly distributed over the length of the lamp container and the metal vapor is kept in vaporous condition in the lamp.

The heat conducting bodies do not surround the discharge path in the lamp so that the discharge between the electrodes is free to develop and fill out the entire cross-section of the tubular lamp container.

llhe invention will be readily understood by an inspection of I accompanying drawing and a perusual of roller/ring detailed description thereof.

Referring to the drawing:

Fig. l is a side eievational, partly sectional. view of one'embodirnent of the invention,

Fig. 2 is a sectional view along the line 2-2 of Fig. 1, and

Fig. 3 is'a similar view of a heat conducting element useful in the lamp shown in Fig. 1.

Like numbers denote like parts in all the figures.

Referring to Figs. 1 and 2 the lamp comprises a tubular container l having a rare, starting gas therein, such as argon, neon, krypton, xenon, or a mixture of such gases, and a body 2 of vaporizable material, such as sodium. A pair of thermionic electrodes 3 are sealed into said container i, one at each end thereof. Each of said electrodes 23 consists of a small rod or bar of compacted and sintered electron emitting material, such as alkali earth metals or the oxides thereof, particularly barium oxide or strontium oxide or a mixture thereof, and a heater filament wrapped around said rod. Said electrodes t are supported by'a pair of current leads l fused into the nipple parts 5 of said container 5. A pair of metal tubes 6 having high heat conducting characteristics, such as iron, nickel or copper tubes are axially mounted in said container i, one at each end thereof, and surround the thermionic electrodes it. Each of the metal tubes 6 absorbs the heat radiated by the electrode 3 and radiates it back to said electrode 3. Said electrodes 3 are thus maintained at an elevated, electron emitting temperature during the operation of the device. I'he tubes 3 are supported in said container 6 by support Wires 7 fused into the nipple parts 5 of the container 5.

An element consisting of two elongated, bisecting flat metal plates 8 of material having good heat conducting characteristics, such as iron, nickel or copper is attached to each of (1 metal tubes ii and extends along the longituc al axis of said container 6 toward the center of said container l. The adjacent ends of said elements 8 are fastened to each other by bodies of insulating material, such as glass rods it. The tubes 6, the elements is and the rods ii are tied together and extend along the longitudinal axis of the container 8.

During the operation of the lamp the elements it absorb the heat generated at the electrodes 3, conduct it along the length of the container l and radiate it in the central portion of said container l. The heat generated in the lamp is thus evenly distributed over the walls of the container l and the metal vapor in the lamp is thus maintained in vaporous condition throughout said container during the operation of said lamp.

The discharge in the lamp develops freely therein and fills the entire cross-section of the con-' tainer i. The discharge also serves to heat the container l.

The heat conducting element illustrated in Fig. 3 of the drawing is useful in the lamp illustrated in Fig. 1 and consists of two corrugated metal sheets it the adjacent ends of which are connected by a body of insulating material, such as glass rods of Fig. 1.

While I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention, for example, other types of thermionic electrodes, such as the directly heated type, are used, when desired; the elements 6 and 8 or 6 and ID are connected as auxiliary electrodes to facilitate the starting of the main discharge, when desired, and an easily vaporizable material, such as mercury, is introduced into said lamp, when desired.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An electric discharge device comprising an elongated container, thermionic electrodes sealed therein at each end thereof, a gaseous atmosphere therein, a metal tube surrounding each of said electrodes, and an element of material having good heat conductivity characteristics around which the discharge between the electrodes occurs, said element being mounted in the disacsaeee charge path between said electrodes, extending around which the discharge between the elec- 1 trodes occurs, said element being mounted in the discharge path between said electrodes, extending from each of said metal tubes and terminating in the mid-part of said container, whereby the heat generated at said electrodes is distributed over the length of said container.

3. An electric discharge device comprising an elongated container, thermionic electrodes sealed therein at each end thereof, a gaseous atmosphere therein comprising sodium vapor, a metal tube surrounding each of said electrodes, and an element of material having good heat conductivity characteristics around which the discharge between the electrodes occurs, said element being mounted in the discharge path between said electrodes, extending from each of said metal tubes and terminating in the mid-part of said container, whereby the heat generated at said electrodes is distributed over the length of said container.

KURT WIEGAND. 

